<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in breadcrumbs" :key="item.path">
        <span
          v-if="item.redirect === 'noredirect' || index === breadcrumbs.length-1"
          class="no-redirect"
        >{{ item.meta.title }}</span>
        <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>
<script lang="ts">
// import pathToRegexp from 'path-to-regexp'
import { Component, Vue, Watch } from 'vue-property-decorator'
import { RouteRecord, Route, RouteRecordPublic } from 'vue-router'
@Component({
  name: 'Breadcrumb'
})
export default class extends Vue {
  private breadcrumbs: Array<RouteRecord> = []
  @Watch('$route')
  private onRouteChange (route: Route) {
    // if you go to the redirect page, do not update the breadcrumbs
    if (route.path.startsWith('/redirect/')) {
      return
    }
    this.getBreadcrumb()
  }

  created () {
    this.getBreadcrumb()
  }

  private getBreadcrumb () {
    // router.getRoutes()获取所有活跃的路由记录列表
    // this.$route是当前激活的路由信息对象
    // this.$route.matched一个数组，包含当前路由的所有嵌套路径片段的路由记录，路由记录就是routes配置数组中的对象副本还有children数组
    // console.log(this.$route.matched)
    // this.$router是router实例
    // console.log(this.$router)
    let matched: Array<RouteRecord> = this.$route.matched.filter(
      item => item.meta && item.meta.title
    )
    const first = matched[0]
    // const homeRoute = this.$router.getRoutes().filter(item => item.path ==='') // 这里猜测是router里面内部对/做了什么处理，所以用空来匹配首页
    if (!this.isDashboard(first)) { // 一般路径会匹配到两个路由这里根据自己的路由表来判断的，所以会先判断是不是首页，如果不是首页，那么会在匹配到的路由前加一个首页的面包屑
      matched = [
        { path: '/dashboard', redirect: '/dashboard', meta: { title: '首页' } } as RouteRecord
      ].concat(matched)
    }
    this.breadcrumbs = matched.filter(item => {
      return item.meta && item.meta.title && item.meta.breadcrumb !== false
    })
  }

  // 判断这个路由是不是首页
  private isDashboard (route: RouteRecord) {
    const name = route && route.name
    if (!name) {
      return false
    }
    return name.trim().toLocaleLowerCase() === 'Dashboard'.toLocaleLowerCase()
  }

  // private pathCompile (path: string) {
  // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
  //   const { params } = this.$route
  //   const toPath = pathToRegexp.compile(path)
  //   return toPath(params)
  // }

  private handleLink (item: any) {
    // console.log(item)
    const { redirect } = item
    if (redirect && redirect !== this.$route.path) {
      this.$router.push(redirect)
    }
    // this.$router.push(path)
  }
}
</script>
<style lang="scss" scoped>
.el-breadcrumb__inner,
.el-breadcrumb__inner a {
  font-weight: 400 !important;
}
.app-breadcrumb.el-breadcrumb {
  display: inline-block;
  font-size: 14px;
  line-height: 50px;
  margin-left: 8px;
  .no-redirect {
    color: #97a8be;
    cursor: text;
  }
}
</style>
